The present invention relates generally to airbags, and more particularly to a method and apparatus for folding an airbag.
From German Patent No. DE 44 22 276 A1 an airbag is known for an airbag module where the collapsed airbag has main folds which run at least in part along closed paths around an imaginary center on the substantially empty spread-out airbag. The closed main folds preferably describe circular paths or ellipses of slight eccentricity. Secondary folds are also provided which arise naturally during collapsing of the airbag.
This path of the main folds has the advantage that the folded airbag can open very quickly and easily. Particularly during the unfolding of such an airbag there is not the danger that the inner pressure produced in partial areas of the airbag will impede the opening of further folds. This airbag can thereby be used for driver, passenger and side airbags. The drawback with this folding is that the expense for folding is considerable particularly if the folding is carried out mechanically.
Furthermore from U.S. Pat. No. 4,173,356 an airbag is known which is folded concertina-like in the direction of the blow-in mouth. The main folds thereby run along parallel straight lines. An airbag thus folded can unfold quickly and simply wherein it is only suitable for passenger or side airbags in this type of folding owing to its elongated shape which is essential for a sufficient volume. It could only be used as a driver airbag if the ends are turned in. There is then however the danger that the inner pressure impedes the opening of some folds.
From U.S. Pat. No. 3,876,272 an airbag is known which has several inner and outer main folds relative to a longitudinal axis. An airbag folded in this way can also unfold rapidly and quickly.
The objective of the invention is therefore to reduce the expense for folding in the case of a universal airbag which is folded so that the inner pressure does not impede the opening of the folds.